This invention relates generally to proximity sensors, and more particularly to methods and apparatus for detecting the proximity of an object using a thermal energy sensor.
At least some known systems are used to monitor the surroundings of a vehicle. Such systems are used, for example, for accident prevention, automatic cruise control (ACC), or observation of the blind spot with respect to the visual field of the driver. Radar sensors, Light Detection And Ranging (LDAR) sensors, ultrasound sensors, and video sensors, for example, are known for determining the location of an object which is present in the surroundings of the vehicle. The various sensors, however, require different considerations for the sensors different detection ranges and characteristics. It is known to combine various sensors to accomplish a monitoring task. However, this results in complex systems because of the necessity to combine the various sensor measurement data. Systems using infrared (IR) detectors have used separate IR detectors and mirror systems to define two fields of view on the road. Each detector and mirror is physically independent of the other leading to significant problems in optically aligning the two separate units so that the relative position of the spots on the road are well defined. The relative alignment is difficult and costly to implement due to requiring a precision housing for the separate units.